
CompactBeamspring
purdeaandrei/CompactBeamSpring
Compact Beamspring Controller, based on the TH Xwhatsit design

Compact Beamspring Controller, based on the TH Xwhatsit design
CompactBeamspringP2 is an open-source printed circuit board by purdeaandrei, from the purdeaandrei/CompactBeamSpring repository on GitHub. It is a 2-layer board of 163.6 × 33.2 mm with 68 parts on 61 nets, routed with 1,158 tracks and 262 vias.
It is built around the MCP4921-E/P, 74AHC595D and LM339AD. Its parts include 24 resistors, 12 capacitors, 12 ICs and 6 connectors. It belongs with the AVR (ATmega, ATtiny) boards of this library.
This controller only supports new style card edge connectors only, and it requires the side of the card edge connector to be cut off, and the pins be bent 90 degress.

This project is based on the Through-hole xwhatsit by listofoptions, which is un turn based on the capsense controllers by XWhatsIt (Tom Wong-Cornall). original liscencure holds, as well as CERN OSH (compatible license).
original implementation of Tom Wong-Cornall's controller documented here
http://downloads.cornall.co/ibm-capsense-usb-web/ibm-capsense-usb.html
Working theory of operation is under the previous link.
| Qty | Value | Footprint | References |
|---|---|---|---|
| 12 | 0U1 | Capacitor_SMD:C_0805_2012Metric_Pad1.15x1.40mm_HandSolder | C1, C1, C2, C2, C3, C3, C4, C4, C5, C5, C6, C6 |
| 8 | 100k 1% | Resistor_SMD:R_0805_2012Metric_Pad1.15x1.40mm_HandSolder | R9, R9, R10, R10, R11, R11, R12, R12 |
| 6 | 74AHC595 | Package_SO:SOIC-16_3.9x9.9mm_P1.27mm | U3, U3, U4, U4, U7, U7 |
| 6 | Not Mounted | Resistor_SMD:R_0805_2012Metric_Pad1.15x1.40mm_HandSolder | R6, R6, R7, R7, R8, R8 |
| 4 | 20K | Resistor_SMD:R_0805_2012Metric_Pad1.15x1.40mm_HandSolder | R3, R3, R4, R4 |
| 4 | 4K7 | Resistor_SMD:R_0805_2012Metric_Pad1.15x1.40mm_HandSolder | R1, R1, R5, R5 |
| 4 | Net-Tie_3 | NetTie:NetTie-3_THT_Pad0.3mm | NT1, NT1, NT2, NT2 |
| 2 | 1K | Resistor_SMD:R_0805_2012Metric_Pad1.15x1.40mm_HandSolder | R2, R2 |
| 2 | BEAMSPRING CONNECTOR | TH-XWhatsIt:30-pin-universal-beamspring-connector_v2 | J1, J1 |
| 2 | Dac Output | TestPoint:TestPoint_Pad_D1.0mm | TP1, TP1 |
| 2 | EXPANSION HEADER | Connector_PinHeader_2.54mm:PinHeader_2x03_P2.54mm_Vertical | J3, J3 |
| 2 | LM339A | Package_SO:SOIC-14_3.9x8.7mm_P1.27mm | U2, U2 |
| 2 | MCP4921-E | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U1, U1 |
| 2 | MountingHole_Pad | TH-XWhatsIt:ChassisGnd | H1, H1 |
| 2 | PadsToShort | TH-XWhatsIt:PadsToShort | J2, J2 |
| 2 | ProMicro | promicro:ProMicro | U5, U5 |
| 2 | Threshold Voltage | TestPoint:TestPoint_Pad_D1.0mm | TP2, TP2 |
The 64 most common of 68 parts.

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It measures 163.6 × 33.2 mm and has 2 copper layers, 1.6 mm thick.
68 parts, built around the MCP4921-E/P, 74AHC595D and LM339AD. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
From the purdeaandrei/CompactBeamSpring repository on GitHub, at the commit this page was made from: the board is CompactBeamspringP2/CompactBeamspringP2.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Its repository states no licence, so its author keeps all rights: ask purdeaandrei before reusing the design.